1. Field of the Invention
The present invention relates to the manufacturing of a golf ball. More specifically, the present invention relates to a method and apparatus for manufacturing a golf ball that involves the use of a laser to primarily remove excess seam material from the golf ball.
2. Description of the Related Art
Golf balls generally have either a one-piece construction or they may comprise several layers including a core, one or more intermediate layers and an outer cover that surrounds any intermediate layer and the core. Golf balls are typically manufactured by various molding processes, whether one-component or multi-component balls. Generally, the core of the golf ball is formed by compression molding, injection molding or the like. If an intermediate boundary layer is desired, one or more intermediate boundary layers are added over the core by any number of molding operations, including casting, compression molding, and/or injection molding. The cover is then formed over the core and intermediate boundary layers, if present, through casting, compression molding, or injection molding.
In an injection molding process, golf balls are typically created by the injection molding of a fluid stock material around a pre-formed core. In the case of a two-component golf ball, the fluid stock material is the cover material used for the golf ball. Injection molding devices generally have two separate and mating hemispheric halves that form a cavity in which the golf ball is created. Fluid stock material is generally fed to the cavity within the mold through one or more conduits, or "runners" as they are commonly referred to in the art. The fluid stock material travelling through the runners enters the actual cavity of the mold via one or more gates. These gates are typically positioned at the parting line created between the interface of the two mold halves. Locating the gates at the parting line, however, results in unwanted material being left on the newly formed golf ball at the parting line. For example, flashing can occur along the equatorial region of the golf ball. In addition, when the gates are located at the parting line of the mold, vestigial stock material located inside the gates of the molding device is attached to the surface of the ball after the mold halves are pulled apart. Additional finishing processes are then required to remove the flashing and any excess material, which can interfere with the dimple pattern on the surface of the golf ball, thereby affecting the performance characteristics of the golf ball.
Similar problems arise with casting a thermosetting polymer cover on a core or multi-layer golf ball precursor product. Typical thermosetting polymer materials include polyurethanes, polyureas, polyether block amides, and the like. A thermosetting cover typically has a flash ring that is tough, and resistant to removal by conventional techniques. The use of thermosetting covers often require that the flash ring be cut prior to sanding or buffing. Additionally, the removal of the flash ring may have a deleterious result on dimples adjacent the parting line depending on the width of the parting line, and the precision of the sanding or buffing device.
One example of a buffing process is Reid et al., U.S. Pat. No. 4,779,387, originally filed in 1986, for a Method And Apparatus For Automatically Buffing A Golf Ball. The Reid patent discloses cutting and sanding to remove a flash ring. The sanding belt (152) of the Reid patent partially deflects about the golf ball during removal of the flash ring.
Another example is Takasaki, U.S. Pat. No. 4,894,958, originally filed in Japan in 1987, for an Apparatus For Scraping Off Burrs At Resin Outer Layer Of A Golf Ball. The Takasaki patent discloses a device that rotates a golf ball while a bite assembly removes the flash ring.
Yet another is Oka et al., U.S. Pat. No. 5,494,631, which was originally filed in Japan in 1992 for an Apparatus And Method For Manufacturing Golf Ball. The Oka patent discloses an apparatus for removing the flash ring from a golf ball that has dimples on the parting line. The Oka patent discloses using a rotating cutting member with a semi-hemispherical surface that is smaller in diameter than a dimple to remove the flash ring inside of a dimple.
Another example is Ihara, U.S. Pat. No. 5,554,337, which was originally filed in Japan in 1994, for Preparation Of Spherical Body. The Ihara patent discloses using an ultrasonic cutter to remove a thermoplastic flash ring from a golf ball. The Ihara patent also discloses that using a laser beam to remove a fin results in scorching of the surface of the golf ball due to laser heat.
The use of lasers to assist in trimming excess material from an object is also disclosed in Millerick et al, U.S. Pat. No. 5,099,101, and Picciolo et al., U.S. Pat. No. 4,539,463. The Millerick patent is for trimming excess material from semiconductor packaging, and the Picciolo patent is for trimming excess material from polyester containers.
A post-mold formation of dimples on a golf ball is disclosed in Oka, U.S. Pat. No. 5,190,294, which was originally filed in Japan in 1990 for a Golf Ball. The Oka patent discloses removing a flash ring, then using a heated trowel to create dimples on the seam line.
Consequently, there remains a need for a more efficient removal of the flash ring on a post-molded golf ball, especially one having a dimples on the parting line.